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Celestial Objects

Celestial objects are usually referred to as Astronomical Objects or Bodies. This term refers to the outer space physical units, associations or formations. Usually, a celestial body is a single entity or unified structure that is joined together by the virtue of a gravitational force like Earth, Moon, Sun, other planets, stars etc. A celestial object / body might be a single body, star huddle or a whole galaxy. Usually, a telescope is needed to view astronomical objects, but there are certain such celestial bodies that are visible even with naked eye. Some of these are huge and close enough to be seen with naked eye like Sun and Moon; others require great eyesight and perfect climate and weather conditions like planets. In this article, I will tell you about some celestial objects that can be seen with naked eye without any difficulty. Let us expand our knowledge.

1. Sun:

Sun is the nearest star to our planet, and this is why we can see it at day without any difficulty at all. In fact, we see with its help in the day time! This certainly isn’t the brightest star of our galaxy; it only is the closest and this is why we do not see other stars in the daytime. In the night, this huge celestial body shines on the other side of the Earth, thus we see stars which are far far away from our planet.

Here are some factual details about this huge star.

Diameter: 1,392,000 kilometers (109 times diameter of the earth)

Mass: 2 × 1030 (3,30,000 times mass of the earth)

Mean distance form the earth: 1.496×108 km

Hydrogen cover ¾ mass of the sun, left mass consists of helium and very little heavier elements for instance oxygen, iron, carbon etc.

As we all now, it is the centre of oursolar system. Every planet of the solar system revolves around this huge bright star. It is a white star, but seems yellow due to the atmospheric scattering of blue light. The surface temperature of sun is around 5505 degree C. It comprises of almost 99.8632% of the total mass of our solar system. A lot of magnetic activity keeps on going on the sun. Its strong magnetic field changes from year to year. After every eleven years, the magnetic field reverses its direction around the solar maximum. This strong magnetic field of the sun is responsible for solar activity like solar flares, solar wind variations and sunspots. Solar activity has, supposedly, played vital role in the formation as well as evolution of the whole solar system. Also, it is responsible for changes in earth’s outer atmosphere, auroras on earth, as well as interrupted radio communication and electric power.

According to what we have been told, this great star was created 4.57 billion years ago due to collapsing of a hydrogen molecular cloud. Looking at the sun directly causes pain and sometimes it can be harmful. Also, viewing a solar eclipse directly can cause serious damage to the eyes of the viewer. Direct exposure to the sunrays is harmful and can cause grave skin ailments. For this purpose, sun blocks and sunscreens are advised to be applied before going out. Sunrays are also being used to produce energy called Solar Energy.

2. Moon:

Moon is a natural satellite, and is the only one Earth possesses. This is the fifth largest natural satellite of our solar system. We can see the moon with naked eye in when the sun sets. Sometimes, we can see it even in the daytime. The moon; though has a very dark surface, is the most bright object in the sky after sun. Its rotation is pretty much synchronized with that of the earth, and this is the reason that we always see the same “face” of moon always. It is also the only celestial object on which humans have landed. Many unmanned spacecrafts have been sent to this natural satellite for further studies. It is the second densest satellite in the solar system, following “Lo”.

Its movement is pretty interesting. In the beginning, it had faster rotation pace, but gravitational forces brought it to a steady speed. The moon takes almost the same time in rotating about its axis as revolving around the earth. Therefore, we always see the same side of the moon called “near side”. The other darker side of the moon is called “far side.”

There are some dark spots that we see on the surface of the moon. These are called “Maria”, which are hardened pools of very old basaltic lava. Maria cover almost 31% of the near side surface, whereas only 2% of the far side surface. Other light colored areas are called “Terrae.” Due to collision of comets and asteroids, various impact craters have been formed on the surface of the moon. Moon is responsible for the high tides in seas and rivers. It is the reason of solar eclipses; which happen when the moon comes in between the sun and the earth. Lunar eclipse occurs when the earth comes in between the sun and the moon, and sun becomes unable to provide illumination to the moon. Thus, we see a lunar eclipse.

It possesses a high status when it comes to cultural mythologies. A calendar is also associated with its name, specifically; the Lunar Calendar.

3. Comet:

Anciently considered as a bad omen when sighted; comets have been observed since old times. It is a small solar system body (SSSB); such object of the solar system which is neither a planet nor a dwarf planet. This is an icy SSSB. It can usually be seen with a tail, due to solar radiations and winds affecting its nucleus. This is why its coma and tail can be seen when it comes close to the sun. These two features distinguishes it form an asteroid. The nucleus is composed of ice, dust, rock and frozen gases. The surface is mostly dry, rocky and dusty. Inner side is believed to be icy.

When acomet is in the outer solar system; it remains unnoticeable. When it reaches the inner solar system, an atmosphere of its own is created around it due to solar wind and radiation. This atmosphere is called coma. The tail is created due to the pressure that is exerted on the coma by solar radiation and wind.

4. Meteoroid:

It is a particle of debris in the solar system, which can be of various sizes. When this debris made celestial object enters the earth’s atmosphere, it transforms into an observable band of light called “Meteor.” It becomes a Fireball when it is brighter than any planet. When the magnitude of a Fireball reaches -14 or brighter, it is called Bolide. A Bolide turns into Superbolide when the magnitude reaches -17 or brighter. A Meteorite is such a meteoroidor asteroid which reaches the surface of the earth undestroyed.

5. Star:

It is a radiant and shining round structure made up of plasma. It is held together by the virtue of gravity. Sun is a star which is visible in the day. Other starsare far away from us and can be seen only in the night; when sun has set. These glittering balls beautify the sky and add up to the charisma of night.